On Smullyans Island you encounter two identical twins You kn

On Smullyan’s Island you encounter two identical twins. You know that one of

them is a Truth-Teller and the other a Liar, though you don’t know which is which.

You also know that one of them is named Fred, but you don’t know whic

h one. (The other is named something else.)

By asking a single three-word question to just one brother (it doesn’t matter which),

you can determine which of the two is Fred (though this would not tell you whether Fred is a Truth-Teller or not). What is that question?

Solution

If I ask other guy that who is Fred that will be his answer?...and opposite to his answer will be fred